The Internet has shown great promise as a means for delivering digital content (e.g., video and audio content, such as television shows, movies and songs). One of the advantages of network-based digital content delivery systems is the ability to deliver digital content to users on an on-demand basis (e.g., video on demand, or VOD). However, content providers have been slow to make content available via the Internet, in large part because of security concerns. Specifically, content providers fear that, once their digital content is available on the Internet, hackers will circumvent any security mechanisms used to protect their digital content and then freely distribute the content. Consequently, system developers are continuously looking for ways to secure digital content and improve the systems by which digital content is delivered over computer networks.
One of the most common ways to protect digital content is to encrypt the digital content so that only a hardware device with access to the proper encryption key can “unlock” and play the digital content. However, this approach is dependent on the ability to secure the encryption key that is used to decrypt the digital content. If a hacker is able to discover the encryption key, then the hacker can use the encryption key to gain unauthorized access to the digital content. Moreover, often times the encryption key can be easily distributed to others so that anyone with the encryption key can gain unauthorized access to the digital content. Accordingly, great care must be taken to secure encryption keys.
One of the ways that hackers attempt to discover encryption keys is by analyzing the hardware and the software routines that operate on the digital content. If a hacker can gain access to a client's system software and/or application software, for example, then the hacker may be able to determine how the system is utilizing an encryption key. Ultimately, this may lead to the discovery of the encryption key. Consequently, it is preferable to prevent hackers from gaining access to system and application software that is stored on a trusted client's disk.
To that end, disk manufacturers have developed disks that can be “locked” with special encryption keys (e.g., disk keys). Accordingly, only a central processing unit with access to the proper disk key can be properly authenticated to gain access to the data on the disk. Among other advantages, this prevents a hacker from removing the disk from the client system, and utilizing the disk in a different system. Of course, the effectiveness of this approach is dependent upon preventing hackers from gaining access to the disk key.